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Provide an Appropriate Response A Frequency Distribution of This Data Set Is Presented Below

Question 84

Multiple Choice

Provide an appropriate response.
-A company's raw-data sample of weekly salaries (in dollars) is shown below.
230340320590780980600350500450460290470400490580570890680410860540530690\begin{array} { l l l l l l l l } 230 & 340 & 320 & 590 & 780 & 980 & 600 & 350 \\ 500 & 450 & 460 & 290 & 470 & 400 & 490 & 580 \\ 570 & 890 & 680 & 410 & 860 & 540 & 530 & 690 \end{array}
A frequency distribution of this data set is presented below, with a third column showing the class midpoints.
 Salary  Frequency  f  Midpoint x200-under 3002250300-under 4003350400-under 5006450500-under 6006550600-under 700 3650700-under 8001750800-under 9002850900-under 10001950\begin{array}{|l|l|l|}\hline \text { Salary } & \begin{array}{l}\text { Frequency } \\\text { f }\end{array} & \begin{array}{l}\text { Midpoint } \\x\end{array} \\\hline 200 \text {-under } 300 & 2 & 250 \\300 \text {-under } 400 & 3 & 350 \\400 \text {-under } 500 & 6 & 450 \\500 \text {-under } 600 & 6 & 550 \\600 \text {-under 700 } & 3 & 650 \\700 \text {-under } 800 & 1 & 750 \\800 \text {-under } 900 & 2 & 850 \\900 \text {-under } 1000 & 1 & 950 \\\hline\end{array}


A) (i) Use the raw data to obtain the sample standard deviation of the ungrouped data. Round your answer to two decimal places.
(ii) Use the grouped-data formula to obtain the sample standard deviation of the grouped data in
The frequency distribution. Round your answer to two decimal places.
(iii) Compare your answers in parts (i) and (ii) . (i) The sample standard deviation of the ungrouped data is 194.48; (ii) The sample standard deviation of the grouped data is 182.52;
(iii) The results in parts (i) and (ii) are different. This discrepancy occurs because in the Grouped data formulas, every actual data value in a given class is replaced by the class Midpoint even though most values in the class are not equal to the midpoint.
B) (i) The sample standard deviation of the ungrouped data is 194.48; (ii) The sample standard deviation of the grouped data is 194.48;
(iii) The results in parts (i) and (ii) are the same. The grouped data formula will always Provide the actual standard deviation when the data are grouped in classes each based on a Single value because the class midpoint is the same as each observation in each class.
C) (i) The sample standard deviation of the ungrouped data is 195.32; (ii) The sample standard deviation of the grouped data is 171.84;
(iii) The results in parts (i) and (ii) are different. This discrepancy occurs because in the Grouped data formulas, every actual data value in a given class is replaced by the class Midpoint even though most values in the class are not equal to the midpoint.
D) (i) The sample standard deviation of the ungrouped data is 171.84; (ii) The sample standard deviation of the grouped data is 171.84;
(iii) The results in parts (i) and (ii) are the same. The grouped data formula will always Provide the actual standard deviation when the data are grouped in classes each based on a Single value because the class midpoint is the same as each observation in each class.

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